Disposable absorbent articles having superabsorbent core structures are well known in the art. Superabsorbent core structures traditionally have at least three functional regions, namely, an acquisition region, a distribution region, and a storage region. The design of these regions and the various materials involved can lead to manufacturing challenges and increased cost.
One conventional superabsorbent core structure includes the use of cellulosic materials. While the use of cellulosic materials provide satisfactory acquisition and distribution, often cellulosic core structures suffer from having poor storage and in addition poor wet integrity (that is, poor structural integrity when wet). Expensive binders may be used in an effort to improve the wet integrity of such cellulosic core structures. Another known problem when using cellulosic materials is the presence of knots and fines. These unsatisfactorily shaped fibers can negatively impact the core properties. The use of cellulosic materials also results in bulky core structures and can lead to undesirably thick or bulky disposable absorbent articles.
Another conventional superabsorbent core structure includes the use of synthetic meltblown fibers. While the use of synthetic meltblown fibers provides satisfactory wet integrity, the resulting core structure can have poor acquisition properties. Further, these meltblown fibers are small and tend to be weak, leading to undesirable core properties. Additionally, synthetic meltblown core structures often require the use of expensive binders.
Conventional superabsorbent core structures for use in disposable absorbent articles may be composite structures, i.e., structures that are made of discrete, multiple layers of materials, including layers of different types of materials. For example, a conventional absorbent core structure may be made of: (a) a top layer which serves as an acquisition region for more immediate absorption of exudate from the wearer, (b) an intermediate layer which serves as a distribution region for the intended transportation of exudate within the superabsorbent core structure and (c) a bottom layer which serves as a storage region for longer term storage of exudate. One of the materials that has been used in the core structure, and especially the bottom layer or storage region, is SAP. This material has been incorporated in various manners, such as by being blown into the bottom layer during manufacture.
Another method of using SAP has been to include the SAP directly in an adhesive. In this situation, the adhesive is used as a carrier for the SAP. The adhesive is then applied to a substrate in areas in which the substantial liquid absorption properties of SAP are desired. Challenges are associated with known ways of combining SAP and adhesive. For example, the adhesive restricts the necessary expansion of the SAP and, therefore, inhibit liquid absorption rates of the SAP. The total liquid holding capacity of the SAP is also reduced because of the entrapment of the SAP within the adhesive. Also, liquid cannot permeate through or past the adhesive in order to contact the SAP. This presents difficulties with respect to arriving at manufacturing processes related to adhesives containing SAP.
It would be desirable to provide a superabsorbent composite core structure that can eliminate or at least reduce problems such as those described above.